Mushroom Poisoning and its Mechanism

PRESENTED BY:SANTOSH PATHAK

IAAS, LAMJUNG CAMPUS

Background

Mushrooms are well known human diet from ancient which have both beneficial and harmful effects .

Some of the mushrooms are known for their nutritional and therapeutical uses whereas some other are known for their toxicity.

Different substances belonging to mushroom poisons are already identified and are related to different signs and symptoms.

Show carcinogenicity, alterations in respirations and cardiac rates, renal failure, rhabdomyolysis (breaking of muscle cells) and other effects are toxicity symptoms of various species including edible and therapeutic ones

About 1,40,000 species of mushrooms have been identified with about 2000 being considered safe for human consumption and about 700 have therapeutic properties.

Some myths about mushroom in Nepal

Poisonous mushrooms discolor silver coins during cooking; edible mushrooms do not.

Mushrooms eaten by cats, dogs, and monkeys are always safe.

Mushrooms eaten by snails or insects are considered safe.

Poisonous mushrooms will lose their poison when cooked with some vinegar.

Mushrooms lose their poison when cooked with timur.

Mushrooms having a fruity smell are safe to eat.

Mushrooms with bitter, acrid, or pungent taste are poisonous.

Smooth-capped mushrooms are edible.

Poisonous Mushrooms

Amanita Clitocybe Cortinarius

Gyromitra Psilocybe

AMANITA SPECIES

Well known for the presence of mainly amatoxins.

Some species also contain phalloin, phalloidin, phallisin, phallacidin, phallacin and phallisacin, virotoxin .

Fig: Amanita pantherina

Toxic Effects

Phallotoxin causes alternations of enterocytes cellular membrane.

Amatoxin inhibits protein synthesis at transcriptional level within enterocytes, hepatocytes and proximal renal tubular cells.

After the ingestion of this mushroom, it causes necrosis of liver cells with mortality rates ranging from about 10-20%.

Some reports have shown that this mushroom causes hallucinogenic effect due to the presence of ibotenic acid.

Symptoms

Motor depression Ataxia (incoordination of muscular movement), Changes in mood Precipitation and feelings Dizziness Gastrointestinal disturbances Drowsiness (sleepy) Muscle twitching.

Treatments

Cholinesterase inhibitors as they counteract the effects of poisoning.

Includes detoxification, careful monitoring and liver transplantation in severe case.

Saline solution should be given to control thirst.

Nitroglycerine and strychnia frequently given upto the limit of tolerance are of great value. Milk is mild antidote.

Atropin may be of use as a stimulant.

CLITOCYBE SPECIES

Fig: Clitocybe spp.

Toxic effects

Caused by acromelic acid (ACRO) which has two isomers- ACRO-A and ACRO-B. ACRO-A has very powerful excitatory action on rat.

Some of the species are poisonous due to the presence of muscarine in their chemical composition.

Symptoms of intoxifications

The patients show paresthesia (abnormal sensation) of the toes and finger followed by paroxysmal (time to time) burning pain notably at night.

A sensation of heat, numbness, odema and local erythema (abnormal awareness of feeling) are associated with cries.

Approximately after 15 minutes to 2 hours of ingestion of this mushroom, patient can present gastrointestinal problems, miosis, hypersecretion and bradycardia (slower heart beat) in severe cases.

Treatments

Atropine can be administered.

CORTINARIUS SPECIES

Comprises between 2000-3000 species of mushrooms

Fig: Cortimarius smithii

Toxic effects

Nephrotoxic due to the presence of the cyclopeptide orellanine.

Also the oxidation of orellanine in renal tissue may accumulate quinone compounds which bind covalently with biological structures leading to cell damage

Symptoms of intoxification

The symptoms of this species appear between 2-20 days after ingestion.

Delayed acute tubulopathy (damage kindney tubules) that can progress to chronic renal insufficiency.

Initially people experience nausea, vomiting and abdominal pain followed by intense thirst, chills, polyuria or oliguria and possibly anuria.

Treatment

Hemodialysis (blood purification) can be done for recreational purposes.

Saline solution can be given for thirst.

GYROMITRA SPECIES

Attractive to hunters and gournets due to their taste.

Some species contain well known toxins like gyromitrin whereas some of them are nontoxic.

Fig: Gyromitra spp.

Toxic effects

They are contained with gyromitrin.

Intoxication occurs due to false cooking method.

Symptoms of intoxication

Symptoms are seen from 8-12 hours after ingestion.

Most common symptoms includes gastrointestinal (vomiting and diarrhea), neurological , liver damage and haemolysis.

The other effects of gyromitrin include carcinogenesis and hepatic problems.

Treatments

It consists of monitoring the symptoms and administrating Vitamin B6 intravenously considering that gyromitrin inactivates this vitamin.

PSILOCYBE SPECIES

Fig: Psilocybe spp

Toxic effects

Species of Psilocybe are known due to their psychedelic effects caused by psilocybin.

Common psylocibin containing mushrooms are : P. semilanceata, P. mexicana, P. bohemica, P. cubensis and P. baeocistis

Symptoms of intoxications

Occurs 30 minutes after ingestion of fresh or dried mushroom with anxiety, nausea, vertigo and asthenia.

Neurosensorial symptoms consists of visual problems, disorientation, motor incoordination .

Sympathom imetic symptoms consists of mydriasis (pupil effects), tachycardia (faster heart rate) and hypertension.

In children, hyperthermia, seizures and comma may be present.

Treatments

Recovery is completed after 4-12 hours of ingestion.

The need of hospitalization is rare and in exceptional cases myocardial infarction (stops blood supply to heart) may occur in adult patients.

Conclusion

Day-to-day, number of intoxications is reported mainly due to misidentification of species.

Hazardous toxins are present in these species and are able to cause different syndromes that can be fatal depending on the amount ingested.

Accidental ingestion of mushrooms is difficult to avoid especially in places where eating wild species is common.

Proper identification is important to avoid accidents and the identification of symptoms and signs of intoxication as soon as possible enables the success of treatment.

Intoxications caused by commonly consumed mushrooms and also the edible mushrooms must be carefully studied.